Internal combustion engines for motor vehicles are known which include a hydraulic system for performing work in addition to lubrication. This work can be used to activate/deactivate cylinders of an internal combustion engine to conserve fuel. Such a hydraulic valve lifter activation/deactivation system can include a hydraulic control valve in a valve housing mechanically connected to a separate solenoid. The solenoid includes a solenoid coil bobbin on which a wire coil is wound and an armature that moves the control valve in response to an input signal (coil electrical current signal) to the wire coil to control hydraulic pressure in the valve lifter oil control gallery. A separate check valve assembly is mounted in a fluid exhaust passage (vent-to-sump) in the engine block or cylinder head and functions to maintain oil pressure in the oil control gallery at a preselected minimum value. Such engine oil control solenoids comprise numerous components which must be assembled together and are known to suffer from hydraulic fluid (oil) leakage through various paths around the solenoid housing.
U.S. Pat. Nos. 6,209,563 and 6,321,767 and 6,581,634 describe engine oil solenoid actuated control valves for controlling a valve lifter activation/deactivation system of a vehicle internal combustion engine. Such engine oil solenoid actuated control valves are communicated to the valve lifter oil control gallery (i.e. receive supply pressure) such that ferrous (paramagnetic) particles in the engine oil supply may migrate or pass through the supply port filters of the solenoid actuated control valve to the solenoid where they can adversely affect performance and life of the control valves.
U.S. Pat. No. 6,581,634 describes an engine oil solenoid actuated control valve for controlling a valve lifter activation/deactivation system of a vehicle internal combustion engine wherein a particle gettering magnet is disposed on the solenoid actuated control valve to magnetically attract and hold ferrous particles in hydraulic fluid supplied to the supply port of the solenoid control valve.
Electronic transmissions for certain motor vehicles are known which include a plurality of hydraulic spool valves each controlled by a respective proportional variable force solenoid actuated control valve of the type described in U.S. Pat. Nos. 5,611,370; 5,996,628; 5,984,259 and 6,179,268. The proportional variable force solenoid control valves regulate hydraulic pressure on the spool valve in response to an electrical signals from an electronic transmission controller to smooth shifting of the transmission at particular shifting points. Such transmission solenoid control valves are communicated to a transmission module fluid supply circuit such that ferrous (paramagnetic) particles in the transmission hydraulic fluid may migrate or pass through the supply port filters of the solenoid actuated control valves to the solenoid where they can adversely affect performance and life of the control valves.